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Christy Woodward <br />September 17, 2008 <br />Page 5 <br />subsurface hydrogeology near the DRAs will also be evaluated based on logging of planned <br />exploration drill holes. The timing of the planned exploration drilling program is dependent <br />on approval of a Plan of Operations by the Bureau of Land Management. <br />Issue 1 <br />The ambient groundwater quality is defined in HRMMR 1.1(5) as the quality of groundwater <br />at the mine site as of January 31, 1994, because the Sunday Mine Group permits were in place <br />at that time. The Sunday Group Mines have been in existence since the -mid 1950s, and it is <br />unlikely that current groundwater quality is significantly different than conditions on January <br />31,1994. However, the quality of groundwater at the Sundae- Group mines on that date is <br />unknown. Therefore, this work plan focuses on evaluating 'ambient groundwater quality by <br />sampling from wells that will be installed upgradient of the existing nune workings. Based on <br />the local hydrogeological framework, it is unlikely that this water has interacted significantly <br />with the underground workings. <br />Issue 2 <br />Evaluation of the direction and rate of gro <br />parameters: hydraulic gradient, hydraulic <br />contributor to estimating the rate of groun <br />can range in nature by up to 9 orders of in <br />hydraulic conductivity based on observed <br />measured groundwater pumping rates. TI <br />estimated based on evaluation of the hydr <br />published sources. <br />undwater flow requires consideration of several <br />conductivity, and effective porosity. The largest <br />dwater flow is the hydraulic conductivity, which <br />agnitude. This work plan includes estimation of <br />drawdown within the West Sunday Mine and <br />to hydraulic gradient and effective porosity will be <br />oeeolozical framework of the mine area and other <br />Issue 3 <br />The potential for theunderground mining operations to affect groundwater quality is related <br />to exposure of mineralized rocks in the aquifer to oxidizing conditions created by mining. <br />These changing conditions-can affect the `natural solubility of constituents contained in the <br />mineralized rock and potent atly affect groundwater quality. The work plan will evaluate this <br />potential effect on groundwater quality by collecting samples upgradient and downgradient <br />of the underground workings and evaluating any observed changes in groundwater quality. <br />Issue 4 <br />In the event that effects to groundwater quality are associated with the mine, it is necessary to <br />evaluate the persistence of these effects as groundwater moves through the rock in the <br />downgradient direction. It is likely that oxidizing conditions present in the underground <br />workings are local in extent, and that groundwater returns to more reducing conditions as it <br />moves away from the underground workings. This work plan will evaluate the persistence of <br />oxidizing conditions and any associated changes in groundwater quality by sampling wells <br />located downgradient from the underground workings.